clone.cs

static class ArrExt
{
    public static T[] Clone<T>(this T[] arr)
    {
        var clone = new T[arr.Length];

        for (var i = 0; i < arr.Length; i++)
            clone[i] = arr[i];

        return clone;
    }
}

//Now you can do this:
var array = new int[123];
var clone = array.Clone();